Method for recycling mine acid wastewater

Abstract

The invention provides a method for recycling mine acid wastewater. The method comprises the following steps: vulcanization for copper deposition: injecting a sodium sulfide or sodium sulfhydrate solution into acid wastewater containing copper and iron to perform copper deposition reaction for 0.5-1.5h, performing solid-liquid separation to obtain clear liquid containing iron and underflow containing copper sulfide slag, and performing press filtration on the underflow containing copper sulfide slag by a plate and frame filter press to obtain a copper concentrate product and waste liquid containing ferrous iron; aeration for iron deposition: adding sodium hydroxide or potassium hydroxide to the clear liquid containing iron to perform aeration for iron deposition, and performing solid-liquid separation to obtain ferric hydroxide or a ferrous iron product and residual liquid; high-temperature calcination: performing high-temperature calcination on the ferric hydroxide or the ferrous ironproduct to obtain a high-temperature calcination product; and washing, drying and grinding: washing, drying and grinding the high-temperature calcination product to obtain a high-purity iron red product. The method provided by the invention is simple in process and low in equipment investment, is capable of performing harmless treatment on acid wastewater and capable of recovering copper concentrate and high-purity iron red products, reduces the accumulation of solid wastes in mines, increases the resource utilization rate, is beneficial to sustainable and healthy development of the mines, and is suitable for application in the hydrometallurgical industry.

Description

technical field [0001] The invention relates to the technical field of metallurgy, in particular to a method for resource utilization of acidic wastewater from mines, which is suitable for application in the hydrometallurgical industry. Background technique [0002] Copper mines produce acidic wastewater such as acid leachate, pit water, raffinate, and electrodeposited barren solution during the mining process. This kind of acidic wastewater contains valuable metals mainly iron and copper. How to choose a technically feasible, economical and reasonable wastewater treatment method to realize the purification of waste liquid and the comprehensive recycling of iron and copper resources has become an important issue in the hydrometallurgical industry. one of the problems. [0003] The known acid wastewater treatment method is the neutralization precipitation method, and the neutralization agent uses lime or limestone. Obviously, this method has the following disadvantages: one ...

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Problems solved by technology

[0003] The known acid wastewater treatment method is the neutralization precipitation method, and the neutralization agent uses lime or limestone. Obviously, this method has the following disadvantages: one is that a large amount of dust is generated during the dosing process, which affects the environment and has a greater impact on the occupational health of operators; The resulting paste has a large amount of slag, low purity and high water content, not only the valuable resources are not fully utilized, but also a lot of money is needed to build storage areas, and there is a possibility of secondary pollution

[0004] In order to solve the above problems, Chinese patent CN101628773 discloses a "process for the treatment of acidic wastewater containing copper and iron in high-concentration mines". This process adopts a first stage of lime neutralization and iron removal, and a second stage of biological sulfide copper precipitation. There are a large number of neutralized gypsum slag, Long bacterial activation time leads to long copper precipitation time, the need to add nutrients such as sodium lactate leads to high cost and harsh condition control and other problems; Chinese patent CN105565395A discloses "a treatment method for copper mine raffinate", which includes iron powder replacement Copper, sulfide and impurity removal, and use sodium hydroxide or calcium hydroxide to add catalyst and oxidant at the same time and heat to 55-85°C for chemical reaction. After aging the product for 2.5-5h, dry it to obtain solid polyferric sulfate product. There is a period of External addition of iron will increase the cost of back-end processing, heating and heating are difficult to apply to mines with large processing capacity, and the obtained polymeric ferric sulfate product has a small application range; Chinese patent CN105218347A discloses "a copper raffinate to prepare high-purity The method of ferrous oxalate ", this method adopts hydrogen peroxide to oxidize ferrous and then uses resin to absorb iron, adopts saturated oxalic acid solution to desorb, iron powder is used to reduce the precipitation desorption solution, adopt acetone to wash the precipitated residue and then dry to obtain ferrous oxalate. After the trivalent iron is easy to precipitate and foul the resin, the frequent adsorption and desorption of the resin is not suitable for the treatment of large-scale high-concentration mine acidic wastewater, and the copper is not properly recovered.

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